/Engine/Plugins/Animation/MLDeformer/MLDeformerFramework/Source/MLDeformerFramework/Public/MLDeformerInputInfo.h
Convert a rotation quaternion to two basis vectors, each represented as 3 floats, so 6 floats in total.
static void RotationToTwoVectorsAsSixFloats ( const FQuat & Rotation, float * SixFloatsOutputBuffer )